44 research outputs found
Agricultural climate change mitigation : Carbon calculators as a guide for decision making
This is an Accepted Manuscript of an article published by Taylor & Francis Group in International Journal of Agricultural Sustainability on 9 November 2017, available online: https://doi.org/10.1080/14735903.2017.1398628. Under embargo. Embargo end date: 9 November 2018.The dairy industry is receiving considerable attention in relation to both its significant greenhouse gas (GHG) emissions, and it’s potential for reducing those emissions, contributing towards meeting national targets and driving the industry towards sustainable intensification. However, the extent to which improvements can be made is dependent on the decision making processes of individual producers, so there has been a proliferation of carbon accounting tools seeking to influence those processes. This paper evaluates the suitability of such tools for driving environmental change by influencing on-farm management decisions. Seven tools suitable for the European dairy industry were identified, their characteristics evaluated, and used to process data relating to six scenario farms, emulating process undertaken in real farm management situations. As a result of the range of approaches taken by the tools, there was limited agreement between them as to GHG emissions magnitude, and no consistent pattern as to which tools resulted in the highest/lowest results. Despite this it is argued, that as there was agreement as to the farm activities responsible for the greatest emissions, the more complex tools were still capable of performing a ‘decision support’ role, and guiding management decisions, whilst others could merely focus attention on key issues.Peer reviewe
Lattice dielectric response of CdCu{3}Ti{4}O{12} and of CaCu{3}Ti{4}O{12} from first principles
Structural, vibrational, and lattice dielectric properties of
CdCu{3}Ti{4}O{12} are studied using density-functional theory within the local
spin-density approximation, and the results are compared with those computed
previously for CaCu{3}Ti{4}O{12}. Replacing Ca with Cd is found to leave many
calculated quantities largely unaltered, although significant differences do
emerge in zone-center optical phonon frequencies and mode effective charges.
The computed phonon frequencies of CdCu{3}Ti{4}O{12} are found to be in
excellent agreement with experiment, and the computed lattice contribution to
the intrinsic static dielectric constant (~60) also agrees exceptionally well
with a recent optical absorption experiment. These results provide further
support for a picture in which the lattice dielectric response is essentially
conventional, suggesting an extrinsic origin for the anomalous low-frequency
dielectric response recently observed in both materials.Comment: 5 pages; uses REVTEX macros. Also available at
http://www.physics.rutgers.edu/~dhv/preprints/lh_cdct/index.htm
Correlations of structural, magnetic, and dielectric properties of undoped and doped CaCu3Ti4O12
The present work reports synthesis, as well as a detailed and careful
characterization of structural, magnetic, and dielectric properties of
differently tempered undoped and doped CaCu3Ti4O12 (CCTO) ceramics. For this
purpose, neutron and x-ray powder diffraction, SQUID measurements, and
dielectric spectroscopy have been performed. Mn-, Fe-, and Ni-doped CCTO
ceramics were investigated in great detail to document the influence of
low-level doping with 3d metals on the antiferromagnetic structure and
dielectric properties. In the light of possible magnetoelectric coupling in
these doped ceramics, the dielectric measurements were also carried out in
external magnetic fields up to 7 T, showing a minor but significant dependence
of the dielectric constant on the applied magnetic field. Undoped CCTO is
well-known for its colossal dielectric constant in a broad frequency and
temperature range. With the present extended characterization of doped as well
as undoped CCTO, we want to address the question why doping with only 1% Mn or
0.5% Fe decreases the room-temperature dielectric constant of CCTO by a factor
of ~100 with a concomitant reduction of the conductivity, whereas 0.5% Ni
doping changes the dielectric properties only slightly. In addition,
diffraction experiments and magnetic investigations were undertaken to check
for possible correlations of the magnitude of the colossal dielectric constants
with structural details or with magnetic properties like the magnetic ordering,
the Curie-Weiss temperatures, or the paramagnetic moment. It is revealed, that
while the magnetic ordering temperature and the effective moment of all
investigated CCTO ceramics are rather similar, there is a dramatic influence of
doping and tempering time on the Curie-Weiss constant.Comment: 10 pages, 11 figure
Effects of nitrogen availability on polymalic acid biosynthesis in the yeast-like fungus Aureobasidium pullulans
Deposition conditions for the growth of textured ZnO thin films by aerosol CVD process
The crystalline orientation of ZnO thin films deposited by an aerosol CVD process is studied with regard to the experimental conditions. The quality of the C-axis oriented growth depended on the substrate temperature, on the deposition rate and also on the hygrometric degree of the carrier gas. The quality of the gold sublayer influenced also the quality of the ZnO textured growth. Under a dry gas mixture N2-O2 at 495°C and with a deposition rate of 35Å/mn, the texture ratio was less than -3.5 and the misorientation σ002 was less than 1.6°
Elaboration par le procédé pyrosol de couches minces texturées de ZnO pour la réalisation de microcapteurs
The crystalline orientation of ZnO thin films deposited by an aerosol CVD process is studied with regard to the experimental conditions. The quality of the -axis oriented growth depended on the substrate temperature, on the deposition rate and also on the hygrometric degree of the carrier gas. The quality of the gold sublayer influenced also the quality of the ZnO textured growth. Under a dry gas mixture N-O at 495 C and with a deposition rate of 35 Å/mn, the texture ratio was less than -3.5 and the misorientation of the 002 line was less than 1.6.L'orientation cristalline de couches minces de ZnO élaborées par le procédé pyrosol est étudiée en fonction des conditions de dépôt. La qualité de la texture selon l'axe dépend de la température du substrat, de la vitesse de dépôt, du degré d'hygrométrie du gaz vecteur et également de la qualité de la sous-couche chrome/or. Pour des dépôts réalisés avec un mélange pur et sec d'azote et d'oxygène à 495 C et pour une vitesse de dépôt de 35 Å/mn, le rapport de texture est inférieur à -3,5 et la désorientation de la raie 002 est inférieure à 1,6